Jim...You can never have enough rodz, reelz, and/or backing! Since you have a limited space, I would go ahead and try the 50# micron...I've not used it in FF applications...In a former life I had "tuff" line on my Calcuttas and it was dynomite...but if you handle it with your waterlogged hands watch out for line cuts! The only bad that I've heard (besides cuts) is if it's spooled loosely, should you get into it again with the drag doing its' thing, it can dig in and bind up...take care to guide it back on properly after a run and you should be fine!
Talk to your local FF dealer and pump him/her for more information...Cheers!
Wade safe!